Association between antenatal steroid exposure and severity of respiratory distress syndrome

Background: Respiratory distress syndrome (RDS) remains a leading cause of morbidity and mortality among preterm neonates. Antenatal corticosteroid (ACS) administration to mothers at risk of preterm delivery is a well-established intervention aimed at accelerating fetal lung maturation. However, the degree to which ACS exposure modulates the clinical severity of RDS across varying gestational age strata and dosing completeness remains incompletely characterized. Methods: This prospective observational study was conducted at a tertiary neonatal intensive care unit (NICU). A total of 312 preterm neonates born between 24 and 34 weeks of gestation who were diagnosed with RDS were enrolled. Neonates were categorized into three groups: complete ACS course (n = 138), partial ACS course (n = 94), and no ACS exposure (n = 80). RDS severity was graded radiologically (Grades I-IV) and clinically using oxygenation indices, duration of mechanical ventilation, surfactant requirement, and length of NICU stay. Results: Neonates who received a complete ACS course demonstrated significantly lower RDS severity grades (Grade I-II: 71.0% vs. 38.8% in the no-ACS group; p< 0.001). Mean duration of mechanical ventilation was markedly reduced in the complete ACS group (3.2±1.8 days) compared to the partial (5.1±2.4 days) and no-ACS groups (7.6±3.1 days; p< 0.001). Surfactant administration was required in 42.0% of the complete ACS group versus 78.8% of unexposed neonates (p< 0.001). Mortality was significantly lower in the complete ACS cohort (5.1% vs. 17.5%; p = 0.003). Conclusion: Complete antenatal corticosteroid administration is associated with a significant reduction in the severity of respiratory distress syndrome, decreased need for mechanical ventilation and surfactant therapy, and improved neonatal survival. These findings underscore the critical importance of timely and complete ACS administration in pregnancies at risk of preterm delivery.